基于Seislet分数阶阈值算法约束的平面波最小二乘逆时偏移

基于平面波编码的平面波最小二乘逆时偏移存在两个问题,即炮数据混叠引入串扰噪音以及平面波道集数目过多又会降低计算效率。针对上述问题,将适用于地震数据的Seislet变换和应用Riemann-Liouville分数阶积分理论的分数阶阈值函数相结合,并将其引入到平面波编码的最小二乘逆时偏移中,实现基于Seislet分数阶阈值算法约束的平面波最小二乘逆时偏移。在实现该方法的基础上,对简单层状模型和复杂模型进行成像测试。结果表明,地震数据在Seislet域中具有较好的稀疏性,且基于Seislet分数阶阈值算法约束的平面波最小二乘逆时偏移能够有效地压制炮数据混叠引起的串扰噪音,同时能够用较少的平面波道集得到与普通方法相同的成像效果,提高了计算效率。

Plane-wave least-square reverse time migration with Seislet fractional threshold algorithm constraint

Least-square reverse time migration using plane-wave coding always has two problems:encoding data will introduce crosstalk noiseand the excessive number of plane records will reduce the computational efficiency.In this paper,the Seislet transform,which is suitable for seismic data,is combined with the fractional threshold function based on the Riemann-Liouville fractional integration theory,which is then introduced into the least-square reverse time migration using plane-wave coding.Numerical tests on the simple layered and complex model show that seismic data have good sparsity in the Seislet domain and the plane-wave reverse time migration based on Seislet fractional threshold algorithm can effectively suppress the crosstalk noise caused by multi-source data.Compared with the traditional method,this proposed method uses less number of plane-wave gathers to obtain the same imaging effect,and can improve the computational efficiency.